组合催化剂WO3+Raney Ni上高效转化菊芋秸秆制乙二醇

采用商业WO₃和Raney Ni为组合催化剂, 以菊芋秸秆为反应原料制备了乙二醇. 菊芋秸秆中含纤维素51.6 wt%、半纤维素10.3 wt%、木质素17.2 wt%、灰分1.7 wt%和水溶性物质19.2 wt%. 木质素对纤维素和半纤维素的转化影响较小, 而水溶性物质的存在抑制了乙二醇的生成, 因此由未经过预处理的菊芋秸秆得到的乙二醇收率只有29.9%. 而经简单的热水预处理可除掉其中的大部分水溶物, 因而乙二醇收率提高到37.6%. 此外, 组合催化剂在经过热水预处理的菊芋秸秆的转化中表现出了更好的循环使用性能. 同时考察了反应温度和时间对菊芋秸秆转化的影响.     

One‐pot Synthesis of Benzamidonaphtho[2,1‐b]furans and Benzamidobenzo[b]furans as Novel Polycyclic Heteroaromatic Compounds

An operationally simple, green and efficient procedure for one‐pot synthesis of novel polycyclic heteroaromatic compounds such as benzamidonaphtho[2,1‐b]furans and benzamidobenzo[b]furans has been developed from the reaction of arylglyoxals, benzamide, and phenols. The reactions were mediated with low amounts of yttrium nitrate hexahydrate as a suitable Lewis acid catalyst without using solvent.     

Reindarstellung,Kristallzüchtung und Kristallstrukturbestimmung von Iodtrioxid

Synthesis, Crystal Growth, and Crystal Structure Determination of Iodine Trioxide For the first time, pure and single crystalline iodine trioxide has been obtained and its identity proven by a crystal structure determination, unambigously. It forms at slow decomposition of orthoperiodic acid in concentrated sulfuric acid at 70°C during 3–6 weeks. The crystal structure (triclinic, P1 ; a = 500.6(2), b = 674.1(3), c = 679.5(3) pm, α = 97.31(3), β = 96.43(3), γ = 105.36(3)°; 1754 independent reflections, R = 0.064) contains one I₄O₁₂ molecule per unit cell. The oxide can be regarded as a mixed anhydride formed by condensation of two molecules H₅IO₆ and HIO₃, each. The axial atoms in an I₂O₁₀ doubleoctahedron are bridged by two IO groups. The pointsymmetry is C_2h. The molecules are connected via short intermolecular oxygen iodine bridges to form twodimensional infinite layers. The crystal structure thus represents an intermediate between molecular and polymeric.     

Preparation and photoelectrocatalytic activity of a nano-structured WO3 platelet film

A tungsten trioxide (WO₃) film was prepared by calcination from a precursor paste including suspended ammonium tungstate and polyethylene glycol (PEG). The ammonium tungstate suspension was yielded by an acid-base reaction of tungstic acid and an ammonium solution followed by deposition with ethanol addition. Thermogravimetric (TG) analysis showed that the TG profile of PEG is significantly influenced by deposited ammonium tungstate, suggesting that PEG is interacting strongly with deposited ammonium tungstate in the suspension paste. X-ray diffraction (XRD) data indicated that the WO₃ film is crystallized by sintering over 400 °C. The scanning electron microscopic (SEM) measurement showed that the film is composed of the nano-structured WO₃ platelets. The semiconductor properties of the film were examined by Mott-Schottky analysis to give flat band potential E_FB=0.30 V vs. saturated calomel reference electrode (SCE) and donor carrier density N_D=2.5×10²² cm⁻³, latter of which is higher than previous WO₃ films by two orders of magnitude. The higher N_D was explained by the large interfacial heterojunction area caused by the nano-platelet structure, which apparently increases capacitance per a unit electrode area. The WO₃ film sintered at 550 °C produced 3.7 mA cm⁻² of a photoanodic current at 1.2 V vs. SCE under illumination with a 500 W xenon lamp due to catalytic water oxidation. This photocurrent was 4.5-12.8 times higher than those for the other control WO₃ films prepared by similar but different procedures. The high catalytic activity could be explained by the nano-platelet structure. The photocurrent was generated on illumination of UV and visible light below 470 nm, and the maximum incident photon-to-current conversion efficiency (IPCE) was 47% at 320 nm at 1.2 V. Technically important procedures for preparation of nano-structured platelets were discussed.     

Defect and electrical properties of nanocrystalline tungsten trioxide

Nanocrystalline tungsten trioxide particles were prepared by a wet-chemical method. Transmission electron microscope (TEM) analysis shows that the average grain size is about 15nm. The oxygen deficiency of nanometre-sized sample is higher than that of ordinary tungsten trioxide. The electric conductivity increases because of high oxygen deficiency. Ironic relaxation polarization and crystallographic shear (CS) planes theory were used to explain the unusual dielectric characteristic of nanocrystalline tungsten trioxide.     

Highly efficient UV–visible absorption of TiO2/Y2O3 nanocomposite prepared by nanosecond pulsed laser ablation technique

Nanostructured TiO₂-based composites are promising materials because of their superior optical, structural, and electronic properties relative to pristine nanostructured TiO₂. The enhanced properties of TiO₂-based composites have been used in several important applications such as gas sensors, solar cells, and photocatalytic applications. In the past, numerous materials have been coupled with TiO₂ to enhance their optical properties. In this work, full-spectrum (UV and Visible) responsive TiO₂ /Y₂O₃ nanocomposite has been synthesized via pulsed laser ablation in liquid (PLA) to study the impact of Y₂O₃ on the structural, morphology, and optical property of the TiO₂. The nanostructured composites prepared were characterized by XRD, Raman spectroscopy, Field-Emission Scanning Electron Microscope (FESEM) attached with Energy-Dispersive X-ray spectroscopy (EDX), Photoluminescence, XPS, and UV–Vis absorbance spectra. The result demonstrates that the coupling Y₂O₃ with TiO₂ not only changes the structural, optical, and morphology of the TiO₂ but also significantly amplified the light absorption characteristics of the TiO₂ within the UV and visible region. The synthesized TiO₂ /Y₂O₃ nanocomposite could potentially be useful for visible-light responsive applications.     

钇与亚胺基二乙酸配合物的合成及晶体结构

合成了钇与亚胺基二乙酸的配合物，用Ｘ射线衍射法测定了配合物的单晶结构，化学式为［Ｙ２｛Ｈ２Ｎ（ＣＨ２ＣＯＯ）２｝（Ｈ２Ｏ）４］（ＣｌＯ４）２·１．２５Ｈ２Ｏ。晶体属三斜晶系，Ｐ１↑－空间群。晶胞参数：ａ＝０．９２５４（１）ｎｍ，ｂ＝０．９９２２（１）ｎｍ，ｃ＝１．０６５８（２）ｎｍ，α＝７１．４８１（１０）°，β＝７７．９５０（１０）°，γ＝６５．３５０（１０）°，Ｖ＝０．８４０１（２）＾３，Ｚ＝     

Characterization of Nitro Arachidonic Acid and Nitro Linoleic Acid by Mass Spectrometry

Nitration of arachidonic and linoleic acids was performed with nitronium tetrafluroborate, nitrogen dioxide, and dinitrogen trioxide. The nitro compounds were separated on HPLC and characterized further on mass spectrometry. Formation of nitro arachidonic acid m/z 348 and nitro linoleic acid m/z 324 were observed with all the reagents. Interestingly, MS/MS of nitro AA and nitro LA showed specific ions m/z 142, m/z 193, and m/z 206 for nitro arachidonic and m/z 156 and m/z 196 for linoleic acid that were common in all three reactions.     

Preparation of AmIV and AmVI in bicarbonate and carbonate solutions using xenon compounds

Xe compounds, XeF₂, Na₄XeO₆, and XeO₃, were used to oxidize Am^III in carbonate and bicarbonate aqueous solutions. XeF₂ and XeO₃ may be used to obtain Am^IV in solutions, whereas Na₄XeO₆ oxidizes Am^III into Am^IV+An^V+Am^VI or into Am^VI if present in excess. XeO³ reacts with Am^III to give Am^IV only under UV irradiation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 953–954, May, 1994.